The present invention relates generally to soil sampling apparatus, and more particularly to a solid head means that prevents soil from entering hollow drive rods attached to the head means.
Geological sampling apparatus for surveying ground soil are well known. Such apparatus usually includes a sampling probe fastened to the lower end of a first drive rod while successive drive rods are serially connected to the first rod to provide a vertical distance appropriate for the level in the ground and earth at which a soil sample is sought. The probe and serially connected rods are directly driven into the ground by a suitable power source such as a hydraulic cylinder. The rods are made of a high strength durable steel.
xe2x80x9cDirect pushxe2x80x9d soil sampling apparatus presently uses an elongated sampling tube connected to the first, lower most hollow rod by an open center head, i.e., the head has a lower nipple section or portion that attaches to the elongated sampling tube while an upper nipple portion of the head is mechanically connected to the lower end of the lowermost hollow drive rod or directly to the driving power source. When the drive rods and power source thrust the sampling tube into the ground the tube can fill with loose soil or wet mud and water as air in the tube is expelled through the open center head and up through the hollow rods. As the driving process continues, loose, wet soil travels up through the open center head and hollow rods where the soil compacts in the rods.
The sampling tube and connecting head are also made of a high strength durable steel as is a lower soil penetrating shoe discussed hereinafter.
Direct push soil sampling apparatus employs a hydraulic cylinder to directly drive (hammer) connecting drive rods, sampling tube, and head into the ground. U.S. Pat. No. 5,606,139 to Kejr is an example of the direct push or drive apparatus. The hollow connecting rods of the apparatus are used to receive internal tooling. One set of such tooling includes serially connected rods (not shown) inserted into and through the hollow rods to a lower pointed plug (not shown) moved into place in a cutting shoe connected to the lower end of the sampling tube by actuation of the solid rods for the purpose of keeping soil from entering the sampling tube during its downward thrust into the ground to the depth and location of sampling.
Another set of tooling involves the insertion of small diameter tubing into the hollow rods for the purpose of pumping water from the bore hole created by the sampling assembly when driven into the ground.
When the connecting rods are compacted internally with soil the tooling obviously cannot be used until the soil is removed, and the process of removing the compacted soil can be extremely difficult. Hammering and beating on the hollow rods is often the method used to remove the soil.
The present invention uses a drive head having a solid body that prevents any travel of mud and soil into the hollow drive rods. Rather, air is vented and expelled from the head when it enters the ground by at least one passageway that extends from a lower portion of the head to an upper sloping surface of the head, the head having a body portion in the configuration of a truncated cone. The cone has a narrow upper end provided with a threaded nipple for attaching to a hollow drive rod while the lower, broader end of the cone has a threaded nipple for connecting to and supporting the soil sampling tube. As the tube and head are driven into the ground a vertical bore hole is created in the ground and earth while loose soil or mud enters the tube as air is vented into the bore hole. The air travels upwardly through the bore hole to the atmosphere above ground. When the above internal tooling is required; the solid head of the invention is removed from the sampling apparatus and replaced by the prior hollow head.